This chapter focuses on the concepts involved in evaluating the clinical diagnostic efficiency of a test. Clinical specificity and clinical sensitivity are first defined in terms of sample false-positive and false-negative rates. Then additional terms are introduced and defined to take the prevalence of a disease into account when evaluating the impact of false-negative and false-positive results in clinical practice. The advantages and shortcomings of various diagnostic efficiency measures are explained.

This chapter is based on material in earlier editions of The Immunoassay Handbook written by Chris Davies, formerly Scientific Advisor at Ortho Clinical Diagnostics, and more recently, International Project Manager for Biotechnology at the Welsh Development Agency. He is currently the Business Development Manager for Life Sciences for the Welsh Government. Chris has achieved global recognition for his ability to explain immunoassay principles through his chapters in The Immunoassay Handbook.

Diagnosis, bias, imprecision, clinical sensitivity, clinical specificity, reference interval, reference range, normal range, positive predictive value, negative predictive value, prevalence, incidence, likelihood ratio, odds ratio, false positive, false negative, screen-positive rate, diagnostic efficiency, receiver operating characteristic (ROC) curve, analytical goals.